1. Field of the Invention
The present invention is broadly concerned with methods for estimating dough development times when using specific wheat flours in doughs. More particularly, the invention is concerned with such methods that are particularly suited for the production of commercial bread products, and that permit a commercial baker to pretest lots of wheat flour to determine optimum dough development times when using the respective flours.
2. Description of the Prior Art
The bread baking industry is a high volume, low profit margin (per unit) food manufacturing industry that often relies on subjective determinations made by operators in the dough mixing area. While improvements have been made in dough mixers to standardize mixing operations, decisions with respect to adequacy of dough mixing are based on operator experience, and such decisions often err on the side of conservatism and result in loss of efficiency and/or productivity.
Dough mixing is a physical, chemical, physiocochemical, and biochemical process, and it is an extremely important step in the conversion of flour and other ingredients into an edible bakery product. The mixing process promotes hydration by exposing new surfaces of the flour particles for interaction with water, blends all ingredients into a uniform dough mixture, and results in dough development. This development involves the stretching of long molecules from an unperturbed state to a more extended configuration. The length of the development stage depends on the time required to extend the large molecules and to orientate them in the direction of shear.
Dough characteristics vary based on ingredients, environment, and operation system, and they can be measured by different kinds of instruments through imitative (mixograph, farinograph, and alveograph), empirical (extensigraph), or fundamental (rheometers) means. Additionally, dough development based on change in physical dough consistency can be determined during mixing by recording the torque on mixer blades or the power consumed. While all of these measurements are based on changes in physical properties of a dough, the physical changes are mostly related to chemical interactions that occur during dough mixing. These chemical interactions are of both covalent (disulfide bonds, glucosidic bonds, peptide bonds) and non-covalent (hydrogen bonds, hydrophobic interactions, ionic bonds, and van der Waals bonds) nature. The physical and chemical reactions occurring during dough processing are related to gluten and water properties, which change during mixing due to interactions with each other and with other ingredients that are present. Measurements of dough characteristics based on chemical interactions are more challenging than those based on physical properties.
Analytical near infrared reflectance (NIR) spectroscopy is a useful and cost effective method of food analysis at ingredient, processing, and product stages of production. It has been used for routine inspections in agricultural and food systems for three decades. Advantages of this technique are rapid measurements, simple preparation of samples, and ease of operation. The major sources of near infrared absorption are the overtones and combination bands of fundamental vibrations in the mid-infrared spectrum from 4000-600 cm−1. NIR spectroscopy has the potential to probe the molecular and chemical changes that occur during dough development because absorbances in the spectra are a direct manifestation of the principal chemical components of dough-water, protein, starch, and fat. Some bakery applications for which MR has been used include the measurement of sucrose, fat, flour, and water content of biscuit dough and monitoring of the staling process of bread.
To provide uniformly consistent dough, mixer operators' grapple with two major variables—flour absorption and mix time. While proper dough development provides consistency throughout the remainder of the production process, bake absorption maximizes the amount of water that can be held by flour, and this often represents the profit margin realized by the baker. In a recent study, NIR was used to predict the processing and product quality characteristics of wheat flour. Within this study, a major conclusion was the ability of NIR to predict bake absorption in the flour with results equal to those of a trained technician's ability to optimize flour absorption. Earlier NIR investigations found that two specific absorbance wavelengths (1160 nm and 1200 nm) varied with mixer power consumption.